In a motor vehicle, it is necessary to cool the oil used in automatic transmissions. The temperature of automotive transmission fluid (or ATF) may reach elevated temperatures during sustained vehicle operation. However, at these elevated temperatures, transmission fluid is known to experience effects such as oxidization, which impacts the lubricative properties of the transmission fluid. In order to avoid a breakdown of the transmission fluid, these high temperatures need to be reduced. To reduce these high temperatures, an automatic transmission may be provided with a heat exchanger in fluid communication with the transmission. The heat exchanger may be referred to as a transmission cooler and may be an oil/air cooler.
One type of heat exchanger is known as a U-flow transmission cooler. In this type of system, transmission fluid is supplied from an inlet tank at a first side of the transmission cooler and is then discharged from an outlet tank at the same side of the cooler in the opposite direction. A U-flow transmission cooler has many advantages, such as simple design and manufacture, which is favorable for packaging. However, one problem with U-flow transmission coolers is that high thermal stresses may result in the inlet and outlet tanks during operation. This problem may occur because the inlet and outlet tanks are where the highest and lowest temperature gradients occur. As such, there is a need for a system that minimizes and/or reduces high temperature gradients and thermal stresses within U-flow transmission coolers.